This invention relates generally to piercing specimen collection containers in an automated hematology analyzer. More particularly, the invention is directed to a self-adjusting tube detector for a hematology analyzer which can accept and verify a plurality of different sizes and types of collection containers.
Automated blood and blood cell analyzers are well known. These analyzers typically utilize a portion of a whole or pre-prepared blood sample. When the blood sample is taken from a subject, it usually is placed into a collection container such as a vial or test tube. With the potential of exposure to highly infectious diseases by an operator, such as the HIV virus or hepatitis, the tube is closed, typically by a rubber stopper. Many types of blood sample sampling devices have been developed, generally following the procedure of piercing the tube stopper to aspirate a portion of the blood sample. The needle probe or cannula then is removed from the tube and the stopper maintains the remainder of the blood sample sealed in the tube.
In automated hematology analyzers, such as a STKS hematology analyzer sold by the assignee of the present invention, Coulter Corporation of Miami, Fla., a plurality of the sample collection containers or tubes are placed into a tube carrier or cassette. The tube cassette then is loaded into the hematology analyzer and moved to an aspiration location. Each collection container or tube individually is moved to the aspiration location and pierced through its stopper by a transfer needle and a portion of the sample removed for analysis in the hematology analyzer.
Currently, there are four major types of tubes, each of which has a different size and shape. Alignment of each tube in the aspiration location is verified by a tube sensor or detector. Once the tube is verified to be at the aspiration location, the hematology analyzer includes a stripper plate which functions to align and seat the tube and stopper for piercing by the transfer needle. One universal stripper plate which preferably can be utilized in accordance with the present invention is disclosed in U.S. Ser. No. 08/250,265, entitled "Universal Stripper Plate", filed concurrently herewith and incorporated herein by reference.
Conventional tube sensors or detectors are adjusted to sense one size (diameter) of tube and generally have a narrow sensing range of tube diameters. For example, if the tube sensor or detector is adjusted and aligned for large diameter tubes, small diameter tubes can be missed altogether or misaligned in the aspiration location. Therefore, when it is desired to utilize another type of tube, the tube sensor or detector has to be adjusted and aligned to accommodate the other type of tube. This adjustment requires a service operation, since it is a critical adjustment to ensure that the tube sensor or detector is aligned and is operating correctly.
It therefore would be desirable to provide a self-adjusting tube detector which can accommodate a wide range of the various types and sizes of tubes, which allows full flexibility in handling the different tubes in the hematology analyzer.